Insurance [Line Items]

No definition available.

Name:	ambc_InsuranceLineItems
Namespace Prefix:	ambc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The valuation allowance as of the balance sheet date to reduce the gross amount of receivables to estimated net realizable value, which would be presented in parentheses on the face of the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

+ References

No definition available.

+ Details

Name:	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the amount of premium revenue on financial guarantee insurance contracts recognized during the period that was accelerated for revenue recognition purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6933581&loc=SL5749298-161291

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the premium receivable for financial guarantee insurance contracts reported in the statement of financial position. This element primarily would consist of those financial guarantee insurance contracts which premiums are to be collected over the contract period, but may, on occasion, include premiums which are to be collected in full at inception, but which straddle a financial reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (c)(1),(5)
-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cash inflow from premiums received for premium receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3367-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumReceivableRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accretion of the discount for premiums receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (c)(4)(iii)
-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumsReceivableAccretionOfDiscountOnPremiumReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase (decrease) in the premium receivable on financial guarantee insurance contracts from changes in the period of the contract.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (c)(4)(i)
-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in the premiums receivable on financial guarantee insurance contracts from adjustments classified as other.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (c)(4)(iv)
-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

+ Details

Name:	us-gaap_FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentOtherAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919253-210447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of expense (reversal of expense) for expected credit loss on premium receivable.

+ References

+ Details

Name:	us-gaap_PremiumReceivableCreditLossExpenseReversal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(5))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

+ Details

Name:	us-gaap_PremiumsReceivableAllowanceForDoubtfulAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase (decrease) in allowance for credit loss on premium receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

+ Details

Name:	us-gaap_PremiumsReceivableAllowanceForDoubtfulAccountsPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of recoveries of premiums receivable that were previously written off as bad debts.

+ References

+ Details

Name:	us-gaap_PremiumsReceivableAllowanceForDoubtfulAccountsRecoveries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of writeoff of premium receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

+ Details

Name:	us-gaap_PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross amount, as of the balance sheet date, due the entity from (a) agents and insureds, (b) uncollected premiums and (c) others, before deducting the allowance for doubtful accounts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.5)
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

Name:	us-gaap_PremiumsReceivableGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	srt_CurrencyAxis=currency_GBP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_EUR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_PremiumsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationBySurveillanceCategoryAxis=ambc_SurveillanceCategoryOneaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationBySurveillanceCategoryAxis=ambc_SurveillanceCategoryTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationBySurveillanceCategoryAxis=ambc_SurveillanceCategoryThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationBySurveillanceCategoryAxis=ambc_SurveillanceCategoryFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationBySurveillanceCategoryAxis=ambc_SurveillanceCategoryOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=us-gaap_StructuredFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=ambc_InternationalFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=ambc_PublicFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_OtherPublicFinanceSectorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_OtherInternationalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_MortgageBackedAndHomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_StructuredInsuranceDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_StudentLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_OtherStructuredFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_SovereignAndSubSovereignMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_InvestorOwnedAndPublicUtilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SecuritiesFinancingTransactionAxis=ambc_HousingRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Detail) $ in Thousands, € in Millions, £ in Millions	3 Months Ended
	Mar. 31, 2020 EUR (€)	Mar. 31, 2020 GBP (£)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Insurance [Line Items]
Allowance for Doubtful Accounts, Premiums and Other Receivables			$ 14,000			$ 9,000
Premiums Receivable, Gross			417,000
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount			187	$ 12,000
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable			416,000	495,000
Premium receipts			12,000	13,000
Adjustments for changes in expected and contractual cash flows			10,000	0
Accretion of premium receivable discount			2,000	3,000
Uncollectable premiums			(2,000)
Other adjustments (including foreign exchange)			(8,000)	2,000
Ending premium receivable			403,000	$ 487,000
Premium Receivable, Allowance for Credit Loss			14,352
Premium Receivable, Credit Loss Expense (Reversal)			5,000
Premium Receivable, Allowance for Credit Loss, Writeoff			0
Premium Receivable, Allowance for Credit Loss, Recovery			0
Financing Receivable, Past Due			1,000
Financing Receivable, 90 Days or More Past Due, Still Accruing			1,000
United Kingdom, Pounds
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable		£ 109	142,000
Ending premium receivable		£ 103	128,000
Euro Member Countries, Euro
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	€ 27		30,000
Ending premium receivable	€ 22		24,000
Accounting Standards Update 2016-13 [Member]
Insurance [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (4,000)
Premiums Receivable [Member] \| Accounting Standards Update 2016-13 [Member]
Insurance [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (3,000)
Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			26,000
Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			4,000
Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			30,000
Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			18,000
Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			340,000
Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			70,000
Structured Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Structured Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			4,000
Structured Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			16,000
Structured Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			18,000
Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			32,000
International Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			157,000
International Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			13,000
International Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
International Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			14,000
International Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			130,000
Public Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			191,000
Public Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			13,000
Public Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Public Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Public Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			178,000
Other Public Finance Sectors [Member] \| Public Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			16,000
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			16,000
Other International [Member] \| International Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			15,000
Other International [Member] \| International Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other International [Member] \| International Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other International [Member] \| International Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other International [Member] \| International Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other International [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			15,000
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			26,000
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			1,000
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			3,000
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			18,000
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			4,000
Structured Insurance [Domain] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			19,000
Structured Insurance [Domain] \| Structured Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Structured Insurance [Domain] \| Structured Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Structured Insurance [Domain] \| Structured Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Structured Insurance [Domain] \| Structured Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Structured Insurance [Domain] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			19,000
Student Loans [Member] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			19,000
Student Loans [Member] \| Structured Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Student Loans [Member] \| Structured Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			3,000
Student Loans [Member] \| Structured Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			13,000
Student Loans [Member] \| Structured Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Student Loans [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			4,000
Other Structured Finance [Member] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			6,000
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			6,000
Sovereign And Sub Sovereign [Member] \| International Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			113,000
Sovereign And Sub Sovereign [Member] \| International Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			13,000
Sovereign And Sub Sovereign [Member] \| International Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Sovereign And Sub Sovereign [Member] \| International Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			14,000
Sovereign And Sub Sovereign [Member] \| International Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Sovereign And Sub Sovereign [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			86,000
Investor Owned And Public Utilities [Member] \| International Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			29,000
Investor Owned And Public Utilities [Member] \| International Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Investor Owned And Public Utilities [Member] \| International Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Investor Owned And Public Utilities [Member] \| International Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Investor Owned And Public Utilities [Member] \| International Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Investor Owned And Public Utilities [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			29,000
Housing Revenue [Member] \| Public Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross			175,000
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category Onea [Member]
Insurance [Line Items]
Premiums Receivable, Gross			13,000
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category Two [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category Three [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category Four [Member]
Insurance [Line Items]
Premiums Receivable, Gross			0
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross			$ 162,000